1. Field of the Invention
The present invention relates to a printer such as a wire dot-matrix impact printer, and particularly to a printer which can effectively suppress noises such as impact noises.
2. Description of the Prior Art
FIG. 1 shows an example of prior art printers of a wire dot-matrix impact type. A printer 101 comprises a printer case 103, a platen 105 and a printing head 107. The printer case 103 has an opening 109 into and from which a printing paper 111 is inserted and discharged. The printing paper 111 is transferred by the platen 105 along a path 113 and printed by the printing head 107.
The opening 109 of the printer 101 faces backward with respect to an operator to avoid noises from bothering the operator. With such an arrangement, however, if a wall is located in front of the opening 109, noises such as impact noises are reflected by the wall to bother the operator. Moreover, merely directing the opening 109 backward will not solve an overall problem of noises in an office.
According to another prior art example shown in FIG. 2, a bare noise-absorbing material 115 is arranged in a printer case 103 of a printer 101 and positioned above a path 113. In addition, the printer case 103 is bent to narrow an opening 109 to suppress noises caused by the printer 101. According to this arrangement, the spectrum of an impact noise caused by the printer 101 is of several kilohertz and has a wavelength .lambda. of several tens centimeters. Therefore, a thickness "t" of the noise absorbing material 115 shall satisfy an equation of t&gt;.lambda./4 to realize a sufficient noise absorbing effect. Namely, the noise absorbing material 115 shall have a large thickness, and, therefore, the size of the printer case 103 becomes large to deteriorate the compactness of the printer 101.
FIG. 3 shows still another prior art example in which a bare noise-absorbing material 117 is disposed between an incoming side 111a and an outgoing side 111b of a printing paper to suppress noises generated by a printer 101. However, the noise absorbing material 117 does not have a noise screening property so that merely placing the noise absorbing material 117 in a path 113 may not help to effectively reduce the noises.
As described in the above, according to the prior art printers of the wire dot-matrix impact type, it is difficult to reduce noises to be emitted through the openings 109 of the printers 101 at the same time to realize the compactness of the printers 101.